EFFECT OF OZONATION ON FREE GOSSYPOL

Free gossypol (FG) is a toxic compound which naturally occurs in cottonseed and its derivates. These products are frequently used as animal feed and FG strongly affect the animal production, healthy and possibly being dangerous to humans. Therefore, alternatives to gossypol destruction must be evaluated. Ozone has been highlighted as a potential technology for detoxification of a wide range of emerging contaminants in water, food and feed. Consequently, this work evaluated the effect of ozonation on FG destruction in cottonseed meal. Ozonation was carried out through percolation of a gas stream rich in ozone up to 90 minutes. Three systems were considered: (1) a static cottonseed meal inside the reactor; (2) mixing the meal inside the reactor each 30 min; and (3) a model system, consisted in a bead of glass pearls covered with FG. Therefore, ozone must react not only with FG, but also with different components on system (1) and (2), being firstly necessary to percolate the bead pores and then diffuse into the particles. On the other hand, the model system presented FG attached only to the surface, allowing the evaluation of the direct reaction. Ozone degraded FG in all the systems, but reaching different maximum levels. The FG reduction in homogenized samples was slightly higher (38%) than samples ozonated without homogenization (24%). On the other hand, FG in glass bead has a higher reduction (75%). It suggests a possible difficulty of gas to achieve the FG inside solid particles, as well as effect of unexposed surfaces due to contact areas. It also proves that ozone is able to reduce FG when gas reaches the molecule, without interference of components of matrix. Therefore, ozonation has potential as a technique for gossypol detoxification in cottonseed products.